Thermal transfer printing using a sublimable dye is a method wherein a transfer medium, which comprises a substrate and a color ink layer thereon, is directly contacted on an image receive sheet and heated by a recording head to heat-transfer the color material or the color ink layer onto the image receive sheet. If full color images are required, a portion of the image receive sheet is subjected to heat transferring three times with each color ink layers, such as cyan, magenta and yellow. If necessary, a black color ink layer is also used to record.
Among heat transfer recording, the use of a sublimable dye provides heat-transferred images similar to the image obtained by using silver salt, but they lack depth (flat image). The printed images also have poor light resistance. Especially, since the recorded image contains three color dyes in mixing form, catalytic fading happens. Also if cyan was recorded on magenta, the magenta image might be retransferred onto the transfer madium and the recording concentration of magenta reduces. The retransferring amount is varied by recording energy and number of transferring steps, thus the recorded images is deteriorated in uniformity. The melting type heat transfer also provides flat image and, when dye is used, has poor light resistance. The retransferring phenomenon may also occur in this method.